126 ATTACK UPON THE CANAL

step of the journey would be duly marked, and
reported by the sea-planes operating from Port Said.

To Djemal, clinging still to the dream of entering
Cairo at the head of a victorious army, the choice of
the central route was correct. The first objective
of an invader of Egypt from the east, after crossing the
Suez Canal, must be the capture of the Sweetwater
Canal at a point behind Ismailia. Once that objective
is achieved the road into Egypt lies open to him.
Danger from the rear is gone. With the water-supply
cut off, the defenders of the Canal must surrender
or perish of thirst. To force, then, the passage of the
Canal at either of its extremities would place the
invader at a disadvantage. If the crossing was made
in the northern sector he would have to fight his way
along the west bank in unfavourable conditions,
on a narrow front and subjected to fire on the flanks.
In the southern sector he would be little better off.
Further, the operation of bridging the Canal in these
localities was peculiarly difficult. The channel is at
its widest, and the terrain of the east bank is in favour
of the defence. There is little cover which the
attackers can utilize, and they are exposed to the heavy
guns of warships moored in the CanaL On the other
hand, in the central sector there are two places which
afford prospect of success: the cutting which carries
the Canal through the plateau of El Gisr, immediately
north of Ismailia, and the cuttings between Tussum and
Serapeum. In neither locality can the defence make
effective use of ships of war : and in both the configura-
tion of the east bank gives advantage to the attackers.

While both tactical and supply reasons thus justified
the selection of the central road as the main line of
advance across Sinai, Von Kressenstein and other
Germans must have felt grave doubts of the issue of
the adventure. To essay the invasion of a country
garrisoned by 50,000 to 60,000 troops, and protected